1. Field of Invention
The present invention relates to a speculum medical device to permit access to treatment sites in the rectum and colon, and, in particular, to an anoscope that is useful in the treatment of hemorrhoids.
2. Background of the Invention
A medical device to permit access to an orifice of the human body is referred to generally as a speculum. Equipment for dilating and inspecting the anus, rectum and colon of a patient is often referred to as an anoscope. An anoscope generally comprises a hollow tubular member that is inserted into the anus and colon. The tubular body dilates the anus and covers the skin of the anal canal. The inner or distal end of the equipment enters the rectum and colon. The distal end is often formed with a gap, notch or slot which is positioned over the site of interest. The interior of the tubular member provides a viewing and access passage for the doctor to inspect and perform procedures at the site of interest. Anoscopes are particularly useful in the inspection and treatment of hemorrhoids. The hemorrhoidal tissue is centred in the notch at the distal end and the tissue tends to bulge into the tubular interior of the anoscope for ready access by a doctor. The tissue may be inspected, sutured or other procedures performed such as a biopsy. An example of a typical anoscope is disclosed in U.S. Pat. No. 4,834,067 to Block.
A common surgery performed in conjunction with an anoscope is a hemorrhoidectomy which involves excision of the hemorrhoid tissue and suturing of the surgically produced wounds. The patient is usually placed under general anesthesia, which entails an inherent degree of risk. In addition, the patient invariably experiences acute pain for many days during the period of recovery, especially when defecating.
The treatment of hemorrhoids by elastic band ligation is credited to Blaisdell who described this technique in Diseases of the Colon and Rectum in 1963. The technique involves placing an elastic band on tissue in the rectum above the area of the hemorrhoid where there is little sensation. The tissue trapped in the band being cut off from its blood supply degenerates and is sloughed, and the elastic band along with the sloughed tissue is passed with the bowel motions. More importantly, however, the resulting healing process causes the tissue in the vicinity to become fixed and prolapse of the hemorrhoidal tissue is minimized. Furthermore, the elastic band ligation technique has been found to give relief of hemorrhoidal symptoms.
Commonly owned U.S. Pat. No. 5,741,273 entitled “Elastic band ligation device for treatment of hemorrhoids” discloses a special tool that is useful for elastic banding of hemorrhoids to avoid suturing. The disclosure of U.S. Pat. No. 5,741,273 is incorporated herein by reference. An advantage of the patented ligation device is that the device may be used without directly seeing the site for banding. Thus, it may be used without an anoscope or any other type of scope or viewing technique. The ligation device is sufficiently small that it can be inserted into the rectum of a patient without major discomfort. For best results, however, the elastic band ligation device is used with an anoscope so that the doctor see the site of interest immediately prior to banding.
In order to provide adequate room for manipulation of the elastic band ligation device or any other inspection or treatment instrument within the interior of an anoscope, it has previously been preferable to use larger diameter anoscopes that are often uncomfortable for the patient. With anoscopes having a diameter larger than 2 to 2½ inches, depending on the patient, it is generally necessary to perform the procedure in an operating room under a general anesthetic which increases the risk and cost of the procedure. The cost of the anesthetic, the operating room and the recovery room can be in the order of $1000 per procedure.
There is therefore a need for an anoscope that is designed to be of sufficiently small diameter that it can be used without requiring a general anesthetic while at the same time permitting manipulation of a medical instrument inserted into the anoscope for improved access to the site of interest in the distal notch of the anoscope.